<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box{
      width:200px;
      height: 200px;
      background-color: skyblue;
    }
  </style>
</head>
<body>
  <div id="app">
    <input type="text" v-model="msg">
    <div class="box">
      {{ msg }}
    </div>
  </div>
  <script src="./vue.js"></script>
  <script>
    const vm = new Vue({
      el: '#app',
      data: {
        msg: 'hello'
      }
    })
  </script>
</body>
</html>
